A070928 Smallest integer >= 0 of the form x^4 - n^3.

0, 8, 54, 17, 131, 40, 282, 113, 567, 296, 1070, 673, 204, 1352, 721, 0, 1648, 729, 3141, 2000, 739, 3993, 2474, 817, 5111, 3160, 1053, 6609, 4172, 1561, 8625, 5648, 2479, 11321, 7750, 3969, 14883, 10664, 6217, 1536, 14600, 9433, 4014, 19792

Offset: 1

Author

Benoit Cloitre, May 20 2002

Keywords

• easy
• nonn

Comments

a(n)=0 if n is a power of 4.

Crossrefs

Cf. A068527.

Programs

Mathematica

si[n_]:=Module[{k=Ceiling[Surd[n^3,4]]},While[!Integer[k^4-n^3],k++];k^4-n^3]; Array[si,50] (* Harvey P. Dale, Jan 03 2021 *)

PARI

for(n=1,100,print1(ceil(n^(3/4))^4-n^3,","))

Formula

a(n) = ceiling(n^(3/4))^4 - n^3.